Server seems to "loose" already loaded style

[geoneutrino]

I'm running tessera with tmstyle which works as intended
Initial start of a profile takes > 10 seconds of processing my profiles (i assume the toXML function in tilelive-tm2style) which is ok, after init the map perfomance in browser is normal

This all works when serving 1 profile. But using multiple profiles (currently 7) the server seems to "cooldown" sometimes profiles that are not often used, after some hours or days. Then the next request to this profiles in a browser will again be slow because the initialisation starts all over. I din't recognize a pattern when this occurs but the main profile used often doesn't seem to be affected only the other ones

Is there a way to prevent this behavior or some configuration possibility to do kindof keepalive or so ?
Thanks